ungalnanban has asked for the wisdom of the Perl Monks concerning the following question:

Hi, I want to get output as 0x23400000345....
in the below example
How to get?
i tried out, but unable to get the answer

$r=0x234;
$t=0x345;

$y=pack('L L',$t,$r);
$x1=unpack('L!',pack('P',$y));
printf("\nThe value is $x1");

[download]

I didn't get constant output

--sugumar--

Replies are listed 'Best First'.
Re: packing and unpacking
by almut (Canon) on Mar 12, 2010 at 09:40 UTC 
    my $r = 0x234;
my $t = 0x345;

my $y  = pack('L L', $t, $r);
my $x1 = unpack('Q', $y);
printf "\nThe value is 0x%x", $x1;   # 0x23400000345

    [download]

    (in case you have a 64-bit perl)

[reply]
[d/l]

      I don't know the 64-bit Perl.
      whether you are mentioning 64-bit processor or ...?

      I am using Perl version 5.8.8

      I ran the given code It shows the following error.
      Invalid type 'Q' in unpack at pack.pl line 9.
      --$ugum@r--
[reply]

        You could also simply try 

        my $x1 = $r << 32 | $t;
printf "\nThe value is 0x%x", $x1;   # 0x23400000345

        [download]

        (though whether this works similarly depends of the build options of your perl)

        P.S.: What exactly do you need this for?  Maybe bigint or Math::BigInt would help.

        Update: 

        use bigint; 

my $r = 0x234;
my $t = 0x345;

my $x1 = $r << 32 | $t;

print $x1->as_hex;

        [download]
[reply]
[d/l]
[select]
        From perldoc -f pack: 
        Q   An unsigned quad value.
    (Quads are available only if your system supports 64-bit
    integer values _and_ if Perl has been compiled to support those.
    Causes a fatal error otherwise.)

        [download]

        (($_="Mzz ojjdloobnf jt uvy5502383")=~y~b-zg2-5c96-81~a-z0-9~s)=~s~~~s; print
[reply]
[d/l]

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